Dickson charge pump is a DC-to-DC converter that takes an input DC voltage, and generates an output DC voltage higher than the input DC voltage. The output DC voltage is a multiplication of the input DC voltage. In addition to the DC input voltage, the circuit requires a clock signal or a pair of complementary clock signal, wherein the amplitude of the clock signal is multiplied to increase the output DC voltage.
Dickson charge pump may include a plurality of stages, each used to push up the voltage generated by the previous stages. Each of the stages may include a diode. Conventionally, the diode was formed of a P-type Metal-Oxide-Semiconductor Field Effect Transistor (PMOSFET) that has one of its source and drain regions as an input node, and the other one of the source and drain regions as the output node. The gate of the PMOSFET is tied to the output node of the PMOSFET. The diode, however, suffers from leakage currents between its body and the substrate, on which the diode is formed. The leakage current causes voltage drop in the output DC voltage. As a result, more stages may be needed to bring the output voltage up to a desirable value.